Deposit and Filter Feeders

Deposit and Filter Feeders
Part 1
a. Deposit feeders obtain their food by consuming organic matter that has settled on the bottom of the sea or lake. Suspension or filter feeders, on the other hand, extract food particles from the water by filtering them out.

b. An example of a deposit feeder is a lugworm, which burrows into the sediment and ingests organic material present in the mud or sand. An example of a suspension or filter feeder is a baleen whale, which filters small organisms like krill from the water column using baleen plates in its mouth.

c. Deposit feeders are typically found on the bottom of the sea or lake, as they consume organic material that has settled there. Suspension or filter feeders, as their name suggests, are found in the water column where they filter food particles from the water.

d. Deposit feeders prefer bottoms that contain mud or sediment rich in organic matter. This provides them with a source of food. Suspension or filter feeders do not have a preference for either mud or sand bottoms since they extract their food from the water column.

e. Detritus is a term used to describe organic matter that has been broken down into smaller particles. Deposit feeders often consume detritus as it settles on the sea or lake bottom, using it as a source of food.

Part 2
a. The average salinity of the oceans is approximately 35 parts per thousand (ppt). Salinity is measured in parts per thousand, which represents the amount of salt (in grams) dissolved in 1 kilogram of seawater.

b. A higher average open ocean salinity would be expected in the desert belts along 25 degrees N & S rather than in the tropics between 5 degrees N & S of the equator. This is because in the desert belts, there is higher evaporation and less rainfall, leading to a higher concentration of salt in the water.

c. Salinity levels differ between the Atlantic Ocean and the Pacific Ocean due to factors such as evaporation, precipitation, and freshwater inputs from rivers. The Atlantic Ocean generally has higher salinity levels compared to the Pacific Ocean due to higher evaporation rates in the Atlantic.

d. Saltwater is denser than freshwater because salt ions increase the density of water. The dissolved salt increases the mass of the water without significantly increasing its volume, resulting in higher density.

e. A rapid change in salinity with depth is called a halocline. A rapid change in temperature with depth is called a thermocline. A rapid change in density with depth is called a pycnocline.

Part 3
Squid, octopus, and cuttlefish are all cephalopods, but they have distinct characteristics:

Squid have elongated bodies, ten arms (including two longer tentacles), and a streamlined shape that enables them to swim quickly through the water. They have a rigid internal shell known as a pen.
Octopus have rounded bodies, eight arms, and lack an external shell. They use their arms for locomotion and are known for their ability to camouflage and change colors.
Cuttlefish have a unique internal shell called a cuttlebone, which helps control buoyancy. They have elongated bodies and can rapidly change color and pattern for communication and camouflage purposes.
While all three are marine organisms, they differ in their physical characteristics and behaviors, allowing them to adapt to different environments and ecological niches within the ocean.